Timing belt tensioner issue. HELP

1975 Kombi

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I'm doing my timing belt.* It's at top dead center, flywheel mark on pointer, cam lock in, injection pump lock in, crank lock in and both the cam sprocket and injection pump sprocket are loose. *

Tensioner marks aligned up and tensioner arm is in the square and nut tightened.* So I tightened up the sprockets and removed the locks and rotated the engine clockwise a few times.* Then I checked the tensioner marks and they are not aligned anymore so I tried to line them up again and no go.* They will not get close.

I put the old tensioner back in and the marks align. I have not rotated the engine yet but will check in the morning.
*
Did I do something wrong?
Is the tensioner crap?
Is this normal?
Is the belt the wrong one?

**** it was all going well until the possible tensioner issue.* lol
 

Nero Morg

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No you didn't do anything wrong. The tensioner is just that, a pulley that's spring loaded to hold tension. The marks won't line up always after initially setting. What's important is that it lines up when setting initially, and that your crank/cam timing is correct after barring the engine over. Just bar over until the crank mark is lined up, if cam lock slides into place easily, you're golden. Don't bother checking the pump with the pin, since you have to adjust dynamic start of injection anyways.
 

Mongler98

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Yea so basically there is a trick here that no one talks about or at least that I can find in a write up. See how the tensioner has an arm that has a 90* bend at the end those seats in a hole for it to tension against?
OK so go back to when you put the belt on but this time put the belt and the tensioner on at the same time and don’t worry about the arm, once everything is close enough to the last bit of the distance to go on the sprockets, use a flat head to push that arm into place as this gives you MUCH more play in the belt to get things lined up. Keeps the cam bolt completely free so that the cam sprocket can rotate without the cam moving? Tighten down the 10mm nut for the tensioner, now tension it properly to its mark, NOW you can verify that everything is spot on, NOW and ONLY NOW can you tighten up the cam sprocket nut by counter holding it with he tool or a homemade sprocket tool.
 

1975 Kombi

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Ok thanks for the info. I've ordered another tensioner just in case this one is toast.
 

Mongler98

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always replace all the moving parts. Contrary to what you would think, the belt being the limit here, its not. the serpentine belt, alternator bearing, idle roller, tensioner, water pump are all the weak link here. change ALL those parts in the kit. its usually the water pump and or the tensioner or roller. don't reuse old parts. The belt actually should lasts a very long time as its following a guide and not really moving all that much and has very low friction compared to all the other moving parts and so forth.
 

1975 Kombi

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173,000K / 108000 miles on original belt. The water pump was just starting to leak and the belt had 1000's of small crack lines. A ticking time bomb. lol. I just bought the Beetle

I replaced everything timing belt related. All new. Rollers/tensioner/water pump. I will check the others. Being a Beetle it's impossible to replace serpentine belt pulley and alt once buttoned up.
 
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Mongler98

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its not the miles on the belt, its the age, same with the seals that keep the water pump bearing dry.
5 years, 80K whatever comes first.
Timb bomb, 10/4 on that!!!! definitely.
 

Genesis

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The easy way to get the belt and sprockets back on (especially the cam sprocket) on an ALH is to remove the top roller. Now it goes on easy. Then put the top roller back on and torque that bolt before you tension anything. Makes what would otherwise be a fight a trivial procedure.
 

KLXD

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How far off are the tensioner marks?

Did you rotate using a wrench on the crank as is correct or the cam or pump? If you don't rotate the crank you put abnormally high tension on the slack side of the belt. You can see the tensioner moving to relieve this tension if you do and it might not go back to its original position.
 

jmodge

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Also peek behind the tensioner to make sure the locating tab is secured in the back cover
 

Powder Hound

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The easy way to get the belt and sprockets back on (especially the cam sprocket) on an ALH is to remove the top roller. Now it goes on easy. Then put the top roller back on and torque that bolt before you tension anything. Makes what would otherwise be a fight a trivial procedure.
Definitely!
 

Mongler98

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Uh, no. You get the tensioner nut snug, just a little, then tension, then tighten. If you tighten the nut, you can't set the tension.
Cheers,
PH
Yes my bad your correct. I meant to say snug it up doe to the way I was going.
I've tried the roller too but always have to fight to get it back on.
 

1975 Kombi

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The one on the left is the new bad one that came in the kit. Now, did I do that somehow. It was aligned perfect before I rotated the engine. It probably was ok and I should have left it even though the marks were way off. It is double the distance of the new VW one on the right.

Now the bad one does rotate and tension well if I only move it half the distance but the marks are way off.
 
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KLXD

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Sounds like you're doing it properly but I have to ask. Did you rotate the tensioner CW when you were setting it?

When the belt is turning the cam and pump there is higher tension on the belt between the cam, pump and crank than when you are setting the tensioner with everything loose.

I suspect whats going on is that the tennsioner doesn't have enough oomph to pull all the slack out of the belt due to its bends from being folded for packaging. When you rotate the motor against the valve springs you pull the belt straight and the tensioner takes up more slack.

Maybe it's cold where you're working making the belt stiffer so it's difficult for the tensioner to pull the belt tight?

I think I'd just get it to TDC again where the the tensioner is showing slack, adjust it again to take up the slack, verify the timing marks and call it good.

I can hear the shrieks of horror already.
 

1975 Kombi

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Yep Clockwise. And the VW tensioner is bang on. I set it up and rotated it and it is still dead center.
 
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